data visualization (dsc 530/cis 602-02)

48
Data Visualization (DSC 530/CIS 602-02) Data and Tasks Dr. David Koop D. Koop, DSC 530, Spring 2017

Upload: others

Post on 18-Dec-2021

5 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: Data Visualization (DSC 530/CIS 602-02)

Data Visualization (DSC 530CIS 602-02)

Data and Tasks

Dr David Koop

D Koop DSC 530 Spring 2017

Programmatic SVG Examplebull Draw a horizontal bar chart

- var a = [6 2 6 10 7 18 0 17 20 6]

bull Steps - Programmatically create SVG - Create individual rectangle for

each item bull Possible solution

- httpcodepeniodakooppenGrdBjE

2D Koop DSC 530 Spring 2017

Databull What is this data

bull Semantics real-world meaning of the data bull Type structural or mathematical interpretation bull Both often require metadata

- Sometimes we can infer some of this information - Line between data and metadata isnrsquot always clear

3D Koop DSC 530 Spring 2017

22

Fieldattribute

item

Items amp Attributes

4D Koop DSC 530 Spring 2017

Items amp Links

5D Koop DSC 530 Spring 2017

[Bostock 2011]

Item

Links

Positions and Grids

6D Koop DSC 530 Spring 2017

Position Grid

Dataset Types

7D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Dataset Types

8D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 2: Data Visualization (DSC 530/CIS 602-02)

Programmatic SVG Examplebull Draw a horizontal bar chart

- var a = [6 2 6 10 7 18 0 17 20 6]

bull Steps - Programmatically create SVG - Create individual rectangle for

each item bull Possible solution

- httpcodepeniodakooppenGrdBjE

2D Koop DSC 530 Spring 2017

Databull What is this data

bull Semantics real-world meaning of the data bull Type structural or mathematical interpretation bull Both often require metadata

- Sometimes we can infer some of this information - Line between data and metadata isnrsquot always clear

3D Koop DSC 530 Spring 2017

22

Fieldattribute

item

Items amp Attributes

4D Koop DSC 530 Spring 2017

Items amp Links

5D Koop DSC 530 Spring 2017

[Bostock 2011]

Item

Links

Positions and Grids

6D Koop DSC 530 Spring 2017

Position Grid

Dataset Types

7D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Dataset Types

8D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 3: Data Visualization (DSC 530/CIS 602-02)

Databull What is this data

bull Semantics real-world meaning of the data bull Type structural or mathematical interpretation bull Both often require metadata

- Sometimes we can infer some of this information - Line between data and metadata isnrsquot always clear

3D Koop DSC 530 Spring 2017

22

Fieldattribute

item

Items amp Attributes

4D Koop DSC 530 Spring 2017

Items amp Links

5D Koop DSC 530 Spring 2017

[Bostock 2011]

Item

Links

Positions and Grids

6D Koop DSC 530 Spring 2017

Position Grid

Dataset Types

7D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Dataset Types

8D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 4: Data Visualization (DSC 530/CIS 602-02)

22

Fieldattribute

item

Items amp Attributes

4D Koop DSC 530 Spring 2017

Items amp Links

5D Koop DSC 530 Spring 2017

[Bostock 2011]

Item

Links

Positions and Grids

6D Koop DSC 530 Spring 2017

Position Grid

Dataset Types

7D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Dataset Types

8D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 5: Data Visualization (DSC 530/CIS 602-02)

Items amp Links

5D Koop DSC 530 Spring 2017

[Bostock 2011]

Item

Links

Positions and Grids

6D Koop DSC 530 Spring 2017

Position Grid

Dataset Types

7D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Dataset Types

8D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 6: Data Visualization (DSC 530/CIS 602-02)

Positions and Grids

6D Koop DSC 530 Spring 2017

Position Grid

Dataset Types

7D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Dataset Types

8D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 7: Data Visualization (DSC 530/CIS 602-02)

Dataset Types

7D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Dataset Types

8D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 8: Data Visualization (DSC 530/CIS 602-02)

Dataset Types

8D Koop DSC 530 Spring 2017

Tables

Attributes (columns)

Items (rows)

Cell containing value

Networks

Link

Node (item)

Trees

Fields (Continuous)

Attributes (columns)

Value in cell

Cell

Multidimensional Table

Value in cell

Grid of positions

Geometry (Spatial)

Position

Dataset Types

[Munzner (ill Maguire) 2014]

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 9: Data Visualization (DSC 530/CIS 602-02)

Assignment 1bull httpwwwcisumassdedu

~dkoopdsc530assignment1html bull Use HTML CSS SVG and

JavaScript bull Part 3 will take longer bull Due next Friday (Feb 10) bull Start soon

9D Koop DSC 530 Spring 2017

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 10: Data Visualization (DSC 530/CIS 602-02)

Sets amp Lists

10D Koop DSC 530 Spring 2017

[Daniels httpexperimentsundercurrentcom]

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 11: Data Visualization (DSC 530/CIS 602-02)

Attribute Types

11D Koop DSC 530 Spring 2017

Attribute Types

Ordering Direction

Categorical Ordered

Ordinal Quantitative

Sequential Diverging Cyclic

[Munzner (ill Maguire) 2014]

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 12: Data Visualization (DSC 530/CIS 602-02)

231 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

12D Koop DSC 530 Spring 2017

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 13: Data Visualization (DSC 530/CIS 602-02)

241 = Quantitative2 = Nominal3 = Ordinal

quantitative ordinal categorical

Categorial Ordinal and Quantitative

13D Koop DSC 530 Spring 2017

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 14: Data Visualization (DSC 530/CIS 602-02)

Sequential and Diverging Databull Sequential homogenous range

from a minimum to a maximum - Examples Land elevations ocean

depths bull Diverging can be deconstructed

into two sequences pointing in opposite directions - Has a zero point (not necessary 0) - Example Map of both land

elevation and ocean depth

14D Koop DSC 530 Spring 2017

[Rogowitz amp Treinish 1998]

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 15: Data Visualization (DSC 530/CIS 602-02)

lar structure of spirals allows for an easy detection of cyclesand for the comparison of periodic data sets Furthermorethe continuity of the data is expressed by using a spiral in-stead of a circle

31 Mathematical description and types of spirals

A spiral is easy to describe and understand in polar coor-dinates ie in the form The distinctive feature ofa spiral is that f is a monotone function In this work we as-sume a spiral is described by

Several simple functions f lead to well-known types ofspirals bull Archimedeslsquo spiral has the form It has the spe-

cial property that a ray emanating from the origincrosses two consecutive arcs of the spiral in a constantdistance

bull The Hyperbolic spiral has the form It is theinverse of Archimedeslsquo spiral with respect to the origin

bull More generally spirals of the form are calledArchimedean spirals

bull The logarithmic spiral has the form It has thespecial property that all arcs cut a ray emanating fromthe origin under the same angleFor the visualization of time-dependent data Archimedeslsquo

spiral seems to be the most appropriate In most applicationsdata from different periods are equally important Thisshould be reflected visually in that the distance to other peri-ods is always the same

32 Mapping data to the spiral

In general markers bars and line elements can be usedto visualize time-series data similar to standard point barand line graphs on Spiral Graphs For instance quantitativediscrete data can be presented as bars on the spiral or bymarks with a corresponding distance to the spiral Howeversince the x and y coordinate are needed to achieve the generalform of the spiral their use is limited for the display of datavalues One might consider to map data values to small ab-solute changes in the radius ie

Yet we have found this way of visualizing to be ineffec-tive We conclude that the general shape of the spiral shouldbe untouched and other attributes should be used such asbull colourbull texture including line styles and patterns

Figure 1Two visualizations of sunshine intensity using about the same screen real estate and thesame color coding scheme In the spiral visualization it is much easier to compare days to spotcloudy time periods or to see events like sunrise and sunset

r f ϕ( )=

r f ϕ( ) dfdϕ------ 0 ϕ R+isingt=

r aϕ=

2πar a ϕfrasl=

r aϕk=

r aekϕ=

r aϕ bv ϕ( ) b πamax v ϕ( )( )---------------------------lt+=

Cyclic Data

15D Koop DSC 530 Spring 2017

[Sunlight intensity Weber et al 2001]

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 16: Data Visualization (DSC 530/CIS 602-02)

Semanticsbull The type of data does not tell us what the data means or how it

should be interpreted bull Tables have keysvalues fields have independentdependent vars

16D Koop DSC 530 Spring 2017

Attribute SemanticsKeys vs Values (Tables) or Independent vs Dependent (Fields)

Flat

Multidimensional

Tabl

es

Fiel

ds

[Munzner (ill Maguire) 2014]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 17: Data Visualization (DSC 530/CIS 602-02)

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 18: Data Visualization (DSC 530/CIS 602-02)

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 19: Data Visualization (DSC 530/CIS 602-02)

Data Model vs Conceptual Modelbull Data Model raw data that has a specific data type (eg floats)

- Temperature Example [325 540 -173] (floats)bull Conceptual Model how we think about the data

- Includes semantics reasoning- Temperature Example

bull Quantitative [3250 5400 -1730]bull Ordered [warm hot cold]bull Categorical [not burned burned not burned]

17D Koop DSC 530 Spring 2017

[via A Lex 2015]

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 20: Data Visualization (DSC 530/CIS 602-02)

ldquoComputer-based visualization systems provide visual representations of datasets designed to help people carry out tasks more effectivelyrdquo

18D Koop DSC 530 Spring 2017

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 21: Data Visualization (DSC 530/CIS 602-02)

Tasksbull Why Understand data but what do I want to do with it bull Levels High (ProduceConsume) Mid (Search) Low (Queries) bull Another key concern Who

- Designer lt-gt User (A spectrum) - Complex lt-gt Easy to Use - General lt-gt Context-Specific - Flexible lt-gt Constrained - Varied Data lt-gt Specific Data

19D Koop DSC 530 Spring 2017

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 22: Data Visualization (DSC 530/CIS 602-02)

Tasks

20D Koop DSC 530 Spring 2017

Trends

Actions

Analyze

Search

Query

Why

All Data

Outliers Features

Attributes

One ManyDistribution Dependency Correlation Similarity

Network Data

Spatial DataShape

Topology

Paths

Extremes

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

Identify Compare Summarize

tag

Target known Target unknown

Location knownLocation unknown

Lookup

Locate

Browse

Explore

Targets

Why

How

What

[Munzner (ill Maguire) 2014]

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 23: Data Visualization (DSC 530/CIS 602-02)

Actions Analyze

21D Koop DSC 530 Spring 2017

Analyze

ConsumePresent EnjoyDiscover

ProduceAnnotate Record Derive

tag

[Munzner (ill Maguire) 2014]

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 24: Data Visualization (DSC 530/CIS 602-02)

Visualization for Consumptionbull Discover new knowledge

- Generate new hypothesis or verify existing one - Designer doesnrsquot know what users need to see - why doesnt dictate how

bull Present known information - Presenter already knows what the data says - Wants to communicate this to an audience - May be static but not limited to that

bull Enjoy - Similar to discover but without concrete goals - May be enjoyed differently than the original purpose

22D Koop DSC 530 Spring 2017

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 25: Data Visualization (DSC 530/CIS 602-02)

ldquo[W]e scientists now understand how important emotion is to everyday life how valuable Sure utility and usability are important but without fun and pleasure joy and excitement and yes anxiety and anger fear and rage our lives would be incompleterdquo mdashD Norman (Emotional Design)

23D Koop DSC 530 Spring 2017

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 26: Data Visualization (DSC 530/CIS 602-02)

Measuring User Experience in Visualizationbull Memorability Capability of maintaining and retrieving information

[J Brown et al 1977] bull Engagement Emotional cognitive and behavioral connection that

exists at any point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull Enjoyment Feeling that causes a person to experience pleasure [16] Pleasure is recognized with occurrent happiness and excitement which can be explained in terms of belief desire and thought [W A Davis 1982]

24D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 27: Data Visualization (DSC 530/CIS 602-02)

HIGH QUALITY DESCRIPTION

LOW QUALITY

DESCRIPTION

MEMORABLE

FORGETTABLE

Memorability

25D Koop DSC 530 Spring 2017

[M Borkin et al InfoVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 28: Data Visualization (DSC 530/CIS 602-02)

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 29: Data Visualization (DSC 530/CIS 602-02)

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 30: Data Visualization (DSC 530/CIS 602-02)

Memorability Maps instead of Networks

26D Koop DSC 530 Spring 2017

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

EUROGRAPHICS 2015 H Carr K-L Ma and G Santucci(Guest Editors)

Volume 34 (2015) Number 3

Map-based Visualizations Increase Recall Accuracy of Data

Bahador Saket1 Carlos Scheidegger1 Stephen G Kobourov1 and Katy Boumlrner2

1Department of Computer Science University of Arizona Tucson AZ USA2Department of Information and Library Science Indiana University Bloomington IN USA

Figure 1 We investigate the memorability of relational data represented with node-link (left-side) and map-based (right-side)visualizations shown are a node-link and a map-based visualization with 200 nodes and 500 links from the LastFM dataset

AbstractWe investigate the memorability of data represented in two different visualization designs In contrast to recentstudies that examine which types of visual information make visualizations memorable we examine the effect ofdifferent visualizations on time and accuracy of recall of the displayed data minutes and days after interactionwith the visualizations In particular we describe the results of an evaluation comparing the memorability of twodifferent visualizations of the same relational data node-link diagrams and map-based visualization We findsignificant differences in the accuracy of the tasks performed and these differences persist days after the originalexposure to the visualizations Specifically participants in the study recalled the data better when exposed tomap-based visualizations as opposed to node-link diagrams We discuss the scope of the study and its limitationspossible implications and future directions

1 Introduction

Researchers have long recognized that the visual display ofinformation can be more effective than tables and numericsummaries [Ans73] We also know that different visual de-signs offer significantly different reading precision [CM84]In contrast we do not understand nearly as well the mem-orability of the data that underlies the visualization Is thedesign of a visualization responsible for how well users willremember its content

In this paper we present evidence that different visualdesigns can impact the recall accuracy of the data being vi-sualized Several recent studies have tested the memorabilityof different types of visualizations [BMG10 BARM12MPWG12 VMTW12 IXTO11 BVB13] These seminal

studies focused on which types of visual information arememorable [BVB13] To the best of our knowledge nostudy has yet been performed to assess long-term memorabil-ity of the underlying data represented in these visualizationsIn this paper we focus on two alternative visualizations forrelational data Specifically we compare node-link visualiza-tions to map-based visualizations

Node-link visualizations date back to 1735 and are a stan-dard way of depicting relational datasets In node-link dia-grams entities are depicted as points (typically dots or circles)in low-dimensional space and two related entities are con-nected with a curve (typically a straight-line segment) Clustermembership is typically indicated by filling each circle witha color that is unique for each cluster

c 2015 The Author(s)Computer Graphics Forum c 2015 The Eurographics Association and JohnWiley amp Sons Ltd Published by John Wiley amp Sons Ltd

[B Saket et al EuroVis 2015]

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 31: Data Visualization (DSC 530/CIS 602-02)

ISOTYPE Visualizationsbull Study [Haroz et al 2015]

- Want quick understanding and ease of remembering

- Does ISOTYPE help bull Results

- Stacked icons allow both length and quantity encoding

- Icons are more memorable - Images that arent used to show

data are distracting

27D Koop DSC 530 Spring 2017

[Image by O and M Neurath Study by S Haroz et al 2015]

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 32: Data Visualization (DSC 530/CIS 602-02)

Memorabilitybull Capability of maintaining and retrieving information

[J Brown et al 1977] bull How to measure

- test users bull How long

- short-term intermediate or long-term bull What types of visualizations

- barlinepie networks graphs etc

28D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 33: Data Visualization (DSC 530/CIS 602-02)

Engagementbull Emotional cognitive and behavioral connection that exists at any

point in time and possibly over time between a user and a resource [S Attfield et al 2011]

bull How to measure total time spent looking at a chart

29D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 34: Data Visualization (DSC 530/CIS 602-02)

Measuring Engagement

30D Koop DSC 530 Spring 2017

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Grid is blurred click for detail

[S Haroz et al 2015]

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 35: Data Visualization (DSC 530/CIS 602-02)

We ran 50 subjects on Amazon Mechanical Turk in 200 trials (5 chart types times 2 questions times 20 repetitions) blocked by chart type Each subject was paid 8 US Dollars for the 30-minute study and all participants were from the USA Exp 4 Results All subjects showed over 92 accuracy allowing incorrect responses to be dropped from analysis without substantially affecting statistical power We also collapsed across the lsquoMorersquo vs lsquoFewerrsquo condition to yield approximately 40 trials per chart type per subject As with the previous experiments we analyzed the results within-subject to determine the per-formance relative to that of the simple bar charts

We found a main effect of graph type on response time (F[4 49]=20 p lt 005 ηp2=002) A Tukey HSD-corrected comparison of all the graph types found that only the super-fluous condition was significantly different from the stand-ard bar graph (p lt 005) as can be seen in Fig 13

This result combined with the results of experiment 1 show that superfluous images hurt both memorability and speed of usability of charts EXPERIMENT 5 INITIAL ENGAGEMENT Although speed can be an important benchmark the aim of some visualizations is to make people pause and look ndash as is often the case in news articles Designers often rely on pic-tographs because they are thought to draw the attention of a reader When perusing through a collection of articles an en-ticing visualization may increase the likelihood that an article will be inspected more closely Will an ISOTYPE visualiza-tion be better at capturing attention than a simple bar chart We ran an experiment that simulated how visualizations are commonly encountered in a peripheral glimpse as thumb-nails among a collection of text and other visualizations com-peting for interest Exp 5 Methods Subjects were presented with a 3x3 grid of items (Fig 14) Each item included a short title above a small slightly blurred thumbnail The thumbnail was either a set of sen-tences about the topic from Wikipedia or a chart related to the topic The subjects were given two minutes to look through the thumbnails They could click whichever item in-terested them to view the information in full screen without pixilation or blur Clicking again returned them to the grid where they could repeat the process No limit was placed on the number or duration of views for each item However af-ter the trialrsquos time had finished everything was removed from the screen They were then presented with a button to begin the next trial We selected 36 topics from the previous experimentsrsquo cate-gories and constructed text a bar chart and a stacked picto-graph chart for each Throughout the experiment each sub-ject encountered each topic exactly once (9 items times 4 trials) A trial included 3 bar charts 3 stacked pictograph charts and 3 pieces of text We tracked the start time and duration of each view

10 subjects (4 women) participated in this experiment Be-cause it was implemented as a Windows desktop application it was run in the lab All subjects were undergraduates and were paid 5 US dollars for the 15 minute duration Exp 5 Results We binned the first minute of viewing into one-second inter-vals and found the portion of subjects viewing each type of item Fig 15 shows a linear fit of these results collapsed across trial For the first few seconds most are at the selec-tion grid However the ISOTYPE visualization takes a quick

(A)

(B)

Fig 14 (A) An example of the selection grid for experiment 5 The title is readable but the details of the content are unrecog-nizable beyond the type of information (B) An example text dis-play that can also been seen in the middle right of the selection grid in (A)

Fig 15 ISOTYPE charts are best at initially engaging subjects to inspect information more closely

Measuring Engagement

31D Koop DSC 530 Spring 2017

[S Haroz et al 2015]

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 36: Data Visualization (DSC 530/CIS 602-02)

Enjoyment Name Voyager

32D Koop DSC 530 Spring 2017

[Wattenberg 2005 wwwbabynamewizardcom]

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 37: Data Visualization (DSC 530/CIS 602-02)

Measuring Enjoymentbull Difference from engagement (eg may be for a job) bull Self-reporting (eg comparison between different charts bull Measure why someone enjoys a visualization

- Challenge - Focus - Clarity - Feedback - Control - Immersion

33D Koop DSC 530 Spring 2017

[B Saket et al BELIV 2016]

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 38: Data Visualization (DSC 530/CIS 602-02)

ldquoVisualizations donrsquot need to be designed for memorability ndash they need to be designed for comprehension For most visualizations the comprehension that they provide need only last until the decision that it informs is made Usually that is only a matter of secondsrdquo mdash S Few

34D Koop DSC 530 Spring 2017

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 39: Data Visualization (DSC 530/CIS 602-02)

Reactionbull B Jones (paraphrased) People make decisions using visualizations

but this isnt instantaneous like robots or algorithms they often chew on a decision for a while

bull R Kosara there are cases where people benefit from remembering a visualization (eg health-related visualization)

bull Are there tradeoffs between the characteristics

35D Koop DSC 530 Spring 2017

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 40: Data Visualization (DSC 530/CIS 602-02)

Visualization for Productionbull Generate new material bull Annotate

- Add more to a visualization - Usually associated with text but can be graphical

bull Record - Persist visualizations for historical record - Provenance (graphical histories) how did I get here

bull Derive (Transform) - Create new data - Create derived attributes (eg mathematical operations

aggregation)

36D Koop DSC 530 Spring 2017

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 41: Data Visualization (DSC 530/CIS 602-02)

MTA Fare Data Exploration

37D Koop DSC 530 Spring 2017

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 42: Data Visualization (DSC 530/CIS 602-02)

Actions Search

bull What does a user know bull Lookup check bearings bull Locate find on a map bull Browse whatrsquos nearby bull Explore where to go (patterns)

38D Koop DSC 530 Spring 2017

Search

Target known Target unknown

Location known

Location unknown

Lookup

Locate

Browse

Explore

[Munzner (ill Maguire) 2014]

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 43: Data Visualization (DSC 530/CIS 602-02)

Query

bull Number of targets One Some (Often 2) or All bull Identify characteristics or references bull Compare similarities and differences bull Summarize overview of everything

39D Koop DSC 530 Spring 2017

Query

Identify Compare Summarize

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 44: Data Visualization (DSC 530/CIS 602-02)

Targets

40D Koop DSC 530 Spring 2017

Trends

ALL DATA

Outliers Features

ATTRIBUTES

One ManyDistribution Dependency Correlation Similarity

Extremes

NETWORK DATA

SPATIAL DATA

Shape

Topology

Paths

[Munzner (ill Maguire) 2014]

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 45: Data Visualization (DSC 530/CIS 602-02)

Analysis Example Different ldquoIdiomsrdquo

41D Koop DSC 530 Spring 2017

[SpaceTree Grosjean et al] [TreeJuxtaposer Munzner et al]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 46: Data Visualization (DSC 530/CIS 602-02)

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 47: Data Visualization (DSC 530/CIS 602-02)

ldquoIdiomrdquo Comparison

42D Koop DSC 530 Spring 2017

[SpaceTree Supporting Exploration in Large Node Link Tree Design Evolution and Empirical Evaluation Grosjean Plaisant and Bederson Proc InfoVis 2002 p 57ndash64]

SpaceTree

[TreeJuxtaposer Scalable Tree Comparison Using Focus+Context With Guaranteed Visibility ACM Trans on Graphics (Proc SIGGRAPH) 22453ndash 462 2003]

TreeJuxtaposer

Present Locate Identify

Path between two nodes

Actions

Targets

SpaceTree

TreeJuxtaposer

Encode Navigate Select Filter AggregateTree

Arrange

Why What How

Encode Navigate Select

[Munzner (ill Maguire) 2014]

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]

Page 48: Data Visualization (DSC 530/CIS 602-02)

Analysis Example Derivationbull Strahler number

ndash centrality metric for treesnetworks ndash derived quantitative attribute ndash draw top 5K of 500K for good skeleton

43D Koop DSC 530 Spring 2017

[Using Strahler numbers for real time visual exploration of huge graphs Auber Proc Intl Conf Computer Vision and Graphics pp 56ndash69 2002]

Task 1

58

54

64

84

24

74

6484

84

94

74

OutQuantitative attribute on nodes

58

54

64

84

24

74

6484

84

94

74

InQuantitative attribute on nodes

Task 2

Derive

WhyWhat

In Tree ReduceSummarize

HowWhyWhat

In Quantitative attribute on nodes TopologyIn Tree

Filter

InTree

OutFiltered TreeRemoved unimportant parts

InTree +

Out Quantitative attribute on nodes Out Filtered Tree

[Munzner (ill Maguire) 2014]